OK, here's a strange one:

Upgrade my wife's machine from 7 to 10. Upgrade seems to go perfectly. Enable Administrator account (because we ALL log in as administrator around here, it's just easier) and all her settings, etc. are there...

...EXCEPT, when I run IE11, the pages don't appear. If I add a site to the compatibility list, it works normally, but otherwise it just doesn't display.

If I run IE11 in other accounts, it works fine, so something loading or some setting in the Administrator account is keeping things from working correctly. I've tried removing things from the startup. I've upgraded 3 other machines here and haven't had this problem. I rolled back to 7 and uninstalled add-ins, etc. and upgraded again, reset the IE11 settings, etc, and it's still doing it.

Any ideas?